Regulatory Capital Requirements (Details) $ in Millions	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)	Jun. 30, 2024 USD ($)
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Adjusted total assets	$ 4,446,000	$ 4,460,000
Risk-weighted assets	1,312,000	1,364,000
Total capital (statutory)
Available Capital (Deficit)	(11,000)	(18,000)
Minimum Capital Requirement	105,000	109,000
Total Capital Requirement (including Buffers)	$ 105,000	$ 109,000
Available Capital (Deficit) Ratio	(0.008)	(0.013)
Minimum Capital Ratio Requirement	0.080	0.080
Total Capital Requirement Ratio (including Buffers)	0.080	0.080
Common equity tier 1 capital
Available Capital (Deficit)	$ (48,000)	$ (56,000)
Minimum Capital Requirement	59,000	61,000
Total Capital Requirement (including Buffers)	$ 139,000	$ 142,000
Available Capital (Deficit) Ratio	(0.037)	(0.041)
Minimum Capital Ratio Requirement	0.045	0.045
Total Capital Requirement Ratio (including Buffers)	0.106	0.104
Tier 1 capital
Available Capital (Deficit)	$ (29,000)	$ (37,000)
Minimum Capital Requirement	79,000	82,000
Total Capital Requirement (including Buffers)	$ 159,000	$ 163,000
Available Capital (Deficit) Ratio	(0.022)	(0.027)
Minimum Capital Ratio Requirement	0.060	0.060
Total Capital Requirement Ratio (including Buffers)	0.121	0.119
Adjusted total capital
Available Capital (Deficit)	$ (29,000)	$ (37,000)
Minimum Capital Requirement	105,000	109,000
Total Capital Requirement (including Buffers)	$ 185,000	$ 190,000
Available Capital (Deficit) Ratio	(0.022)	(0.027)
Minimum Capital Ratio Requirement	0.080	0.080
Total Capital Requirement Ratio (including Buffers)	0.141	0.139
Core capital (statutory)
Available Capital (Deficit)	$ (19,000)	$ (26,000)
Minimum Capital Requirement	111,000	111,000
Total Capital Requirement (including Buffers)	$ 111,000	$ 111,000
Available Capital (Deficit) Ratio	(0.004)	(0.006)
Minimum Capital Ratio Requirement	0.025	0.025
Total Capital Requirement Ratio (including Buffers)	0.025	0.025
Tier 1 capital
Available Capital (Deficit)	$ (29,000)	$ (37,000)
Minimum Capital Requirement	111,000	111,000
Total Capital Requirement (including Buffers)	$ 134,000	$ 135,000
Available Capital (Deficit) Ratio	(0.007)	(0.008)
Minimum Capital Ratio Requirement	0.025	0.025
Total Capital Requirement Ratio (including Buffers)	0.030	0.030
Senior preferred stock	$ 120,836	$ 120,836	$ 120,800